The traditional electric tool can only be used to rotate the screw driver or drill, but it is sometimes difficult to drill a hole or drive out the screw due to material characteristic or the screw too tight. Some improved electric tools have been developed, which consist of an output axis that can be switched to pure rotation mode or rotation with axial vibration so that the drill can be easily drilled into the target body or the tight screw be screwed out of the target body. Taiwan Patent NO. 87210470 is disclosed to provide a screw button switch device with rotation and vibration characteristic to facilitate the operation of the electric tool. However, the above device has to rotate the screw button about 360.degree. to switch the operation mode of the output axis between pure rotation and rotation with axial vibration. Additionally, numbers of components are too much and the whole structure is more complicated as a result of higher cost of manufacturing. Therefore, the present invention is provided to overcome the above shortcomings.